1. Field of the Invention (Technical Field)
The present invention relates to devices and methods for evaluating damage to windows, including aircraft-mounted infrared windows with surface damage due to high speed impacts with sand and dust particles.
2. Description of Related Art
Infrared windows must periodically be evaluated for transmission loss resulting from surface damage due to high speed impacts with sand and dust particles in flight. Currently, these windows have to be removed for evaluation back at the window supplier. Typically this requires removal of the window from the aircraft in which the window is mounted, sending it back to a supplier, and measuring it with an infrared instrument costing on the order of $250,000. Thus, a need exists for making such evaluations in the field and/or in situ with inexpensive equipment.
It has been suggested that a portable scatter meter would make adequate measurement, but such an instrument was tried on the same samples used in testing of the present invention and the correlation was poor. Furthermore, this purportedly alternative device contains a laser, complicating its use in the field.